The present invention relates generally to a method of applying a metal on a substrate surface.
In prior art many different methods of applying a metal on a substrate surface are described.
WO 98/34446 discloses a method to apply conducting materials in distinct patterns on organic substrates, the surface layer is chemically modified to achieve distinct adhesion areas according to said distinct pattern, after which conducting material is applied to these areas.
WO 2007/116056 discloses a method for applying a metal on a substrate, comprising: a) producing polymers on the surface of the substrate, where the polymers comprise carboxylic groups and adsorbed ions of at least one other metal, b) reducing the ions to the second metal and c) depositing the first metal on the reduced ions. Plasma treatment is mentioned as in an initial step in order to improve the wetting of the subsequent solutions that are applied to the surface, and as a cleaning step.
WO 2007/116057 discloses the above process applied to paper.
A large problem today is the industrialization of the full additive processes regarding handling and productivity in production. Today processes with wet grafting chemistry are used. This creates problems in the production lines when it comes to handling and robustness.
No method fulfills the requirements with regards to: Handling of parts in the process, robustness. Productivity and line speed. Grafting onto different polymer surfaces. For instance it is a problem in the state of the art to apply metal onto inert and sensitive materials. Example of a sensitive material includes but is not limited to PC-ABS. Further halogen containing materials are known to be difficult to coat. A process which allows coating of both 2D and 3D substrates is also difficult to obtain.
Sensitive substrate cannot always be coated using the methods according to the state of the art, since the substrate may be sensitive to the grafting chemicals and/or process conditions.
Another problem in the prior art is the use of some photoinitiators in connection with production of polymers on a surface, since many photoinitiators tend to crystallize. For instance benzophenone is difficult of impossible to use as a photoinitiator in many applications because it forms crystals.